<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8">
<title>Title</title>
</head>
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<a href="./04_load事件.html">去哪个 load 页面</a>
<script>

window.onunload = function (){
    alert("你要残忍离开这个页面了吗?");
//    console.log("a");
}
</script>
</body>
</html>